...However, the earthquake in Japan, in addition to damaging the ability of the control rods to regulate the fuel — and the reactor’s coolant system — appears to have damaged the containment facility, and the explosion almost certainly did. There have been reports of “white smoke,” perhaps burning concrete, coming from the scene of the explosion, indicating a containment breach and the almost certain escape of significant amounts of radiation.
At this point, events in Japan bear many similarities to the 1986 Chernobyl disaster. Reports indicate that up to 1.5 meters (4.9 feet) of the reactor fuel was exposed. The reactor fuel appears to have at least partially melted, and the subsequent explosion has shattered the walls and roof of the containment vessel — and likely the remaining useful parts of the control and coolant systems.
It's still possible to contain the mess UNLESS the floor cracked, in which case 'containment' will be impossible.
Pretty high rad-count over there, too, at ~640 rems/hour. That's ~24x 'normal' exposure, with 'normal' being what the average human gets every day from just walking around. NB: See Combox for updates/nuke-engineer recommendations/thoughts.
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From what I can gather - spotty info - the building, which is the secondary containment, went probably from a buildup of hydrogen. Primary containment, the metal structure around the actual reactor is still intact. Also, control rods were inserted to stop the reaction (BWRs are slow reactors). The issue with the exposed fuel is residual heat that will melt the rods that hold the pellets. The fuel won't explode unless you have a runaway reaction - which is what Cheyrnoble was.
Get something more accurate than Hoft, please.
http://www.iaea.org/press/
http://www.nei.org/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region
D29 - I have no sources for inside information on the nuclear aspects of the Japanese disaster.
I will defend the UCS's nuclear power expert, Dave Lochbaum. I used to share an office with the guy and he is an honest critic of the industry. He has a pretty good summary at the ucsusa.org website. That report was the first I saw identifying the Fukushima reactor as a BWR, the tall offgas stacks make it obvious this was a BWR. There are no operating BWR's in WI, but they are located in IL, IA & MN.
The most disturbing part of this from U.S. plant applicability standpoint was the loss of the diesel generators. DG's can be a problem to start, but there is no reason they should shut down after an hour. If there was some new, unknown, failure mode it could have cause significant problems in the U.S.
The tsunami hitting an hour after the quake explains the lost of emergency DG power. This will result in retrofits at coastal U.S. plants, but have little impact elsewhere.
The best information I've found on Fukushima is at the Capacity Factor. http://uvdiv.blogspot.com/
He has post cutaway graphics of a GE Mark I BWR containment.
Sorry, HB. I've been in the business and I have no use for any "expert" from UCS. Don't know this guy from Adam, but I've caught UCS in more BS than I can count. I'll trust IAEA and NEI long before UCS.
I will, however check out Capacity Factor.
We had a crew over at Fuku working on the other reactor for shutdown maintenance. Communication with them is very difficult, but they all seem to be accounted for and safe and moving south out of the damage zone.
If they are flooding primary containment now with borated seawater, they obviously can't maintain the level of water needed in the reactor itself. Last resort, but it was designed that way.
Confirmed that it was hydrogen.
I believe Lochbaum was an SRO at Browns Ferry. He found a good gig at UCS. High visibility, good pay, and no responsibilities. I can't hold that against him.
Thanks for an-almost-first-hand update.
;-)
Hydrogen indicates Zirc-Water reaction from an uncovered core.
The Japanese confirmed that about 4-5' of the rod bundles had been exposed. Major LOCA. But more 3 Mile than Cheyrnoble.
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